中鋒 (美式足球)

Centers play an integral part of the offensive line and act as the primary protector of the quarterback after the snap. The center is often referred to as "the smartest person on the field next to the quarterback", in the sense that the center acts as the line's "mind". Before the snap, the center is given the responsibility of assessing the likely action of the defensive team (based on his knowledge of their defensive schemes, as well as the placement and stance of players on the field) and will then often adjust the blocking assignments of all the offensive linemen and the backfield by communicating using audible and visual signals referred to as "line calls".

On most plays, the center will snap the ball directly into the quarterback's hands. In a shotgun formation, the center snaps the ball to the quarterback lined up several yards behind him.

After the snap, the center must block defensive players from reaching the ball carrier (on running plays) or the quarterback (on passing plays). On passing plays in particular, the center often must block blitzing defensive players.

In special teams situations, the center is referred to as a "long snapper," who snaps the ball with two hands to a punter standing approximately 12-14 yards behind him, or to the holder for the placekicker, kneeling approximately 7 yards behind him. These long snappers are often players particularly talented at performing these snaps, and are not necessarily the same center used on other plays. In fact, professional football teams may carry a player on their roster for the sole or primary purpose of long snapping.

Although the quarterback commands the ball, it is the center's snap that renders the ball in play; the defensive line may not cross the line of scrimmage until the center snaps the football. An astute center can help draw an opposing team offside prior to the snap or potentially trick the other team into a penalty by quickly snapping the ball while the opposing team attempts to substitute players.